Increasingly it is desired to improve a fuel economy of vehicles, particularly, although not exclusively, vehicles powered by fossil fuels, such as petrol and diesel. Although it will be realised that improving the fuel economy of any vehicle, including electric, hybrid and hydrogen powered vehicles, for example, is also desired. Some efforts at improving the fuel economy of vehicles are focussed on increasing an efficiency of the vehicle, such as a mechanical and/or electrical efficiency of the vehicle. It has also been realised that the manner in which a vehicle is driven can have a significant impact of the vehicle's economy.
People often drive at speeds that are inefficient in terms of fuel consumption. This is often because they do not know an appropriate, efficient speed at which to drive. In addition, there is a significant variation in fuel efficiency from vehicle to vehicle, vehicle type to vehicle type, and from driver to driver based on their driving style. Driving in a way which is more fuel efficient can reduce the harmful pollutants emitted from a vehicle, and reduce the cost of the fuel used during a journey. Furthermore, a fuel-efficient driving styles can reduce the stress on the components of the vehicle, for example the engine, resulting in increased durability for these vehicle components.
Therefore it is desired to provide a method to determine a recommended speed for a vehicle that optimises fuel efficiency. It is also desirable to provide a method by which vehicle driving can be evaluated with respect to such a determined recommended speed.